The process of production of clay minerals having a lipophilic characteristic (“organoclays”) using ammonium quaternary salts to give to clay minerals said lipophilic characteristic is known. Clay minerals, especially smectite, are a class of minerals that contain in their structural formula dioctahedral aluminous species which can be represented by the formula[(Al(2−y)Mgy)(Si(4−x)Alx)O10(OH)2][M(x+y)]nH2Owherein:    x is the amount of aluminum atoms exchangeable from octahedral sheet, and    y is the amount of silicon atoms exchangeable from tetrahedral sheet, and    M(x+y) are monovalent cations present in the clay structure to compensate the resultant charge after the exchange of aluminum and silicon have occurred into the octahedral and tetrahedral sheets, respectively.
Regarding the total amount of cation exchangeable capacity, (x+y) comprises the range 0.2≦(x+y)≦0.6. This range represents the minimum and maximum milliequivalents of cation exchangeable in 100 g of clay mineral.
U.S. Pat. No. 2,531,427 discloses that if M(x+y) is exchanged by an ammonium quaternary salt two different effects are observed in the clay mineral. The replacement of the cation by the ammonium quaternary salt causes an enlargement of the distance between layers of the clay mineral, and the clay mineral surface becomes hydrophobic because of the presence of the alkyl groups introduced by the ammonium quaternary salt. The objective of that invention was to provide a modification of the clay mineral by replacing the interlayer cation by amines in order to give to the clay mineral surface a substantial gelling characteristic which swelled when dispersed in an organic liquid.
Further state of the art is summarized as follows.
U.S. Pat. No. 3,467,208 discloses the application of bentonite treated by long-chain amines in order to give good thixotropy for an oil based drilling mud and to avoid the fluid loss during the well drilling process.
U.S. Pat. No. 3,831,678 discloses the use of a clay which has been organically functionalized by dimethyltallow hydrogenated ammonium salts as viscosifier in oil based drilling fluids.
U.S. Pat. No. 4,752,342 teaches a process for the replacement of sodium by an ammonium quaternary salt in a clay mineral.
The state of the art presented above does not present any disclosure about encapsulation or co-encapsulation of biocidally active ingredients interlayer of the clay minerals. It discloses the preparation of organophilic clays with several types of amines and ammonium quaternary salts.
U.S. Pat. No. 5,164,096 discloses the use of biocide contained within the core of the microcapsules made of a gum gelatin membrane. These microcapsules are used to treat a water system by controlled release of the biocide actives.
WO-A-93/02668 discloses the microencapsulation of at least one active ingredient, contained in an hydrophilic internal core, coated by a coat of copolymer of ethylene and vinyl acetate (EVA) or a copolymer of vinylidene chloride and vinyl chloride and other types of polymers.
U.S. Pat. No. 6,165,485 discloses that a bentonite based organoclay, when mixed with a biocidal quaternary amine containing a benzyl molecule within its structure, acts as a reasonably effective biocide.
U.S. Pat. No. 6,521,678 describes a method for preparing organoclays with a substantially monomolecular layer of water soluble polymer to the clay; applying a surfactant to the clay to modify the hydrophilic/hydrophobic balance of surfaces of the clay and separate out the organoclay from the water.
U.S. Pat. No. 7,429,392 discloses the use of biocides bonded to solid resins particles in order to confer antimicrobial protection to highly alkaline coating films, e.g. paints, leading to higher stability in the pH of the paint and delayed release of the biocide.
It has been observed that there are biocidally active ingredients that cannot be encapsulated into organophilic clay using the encapsulation modifiers of the state of the art. The problem of the instant invention was to find an encapsulation modifier that allows such biocidally active ingredients to be encapsulated in a clay mineral.
It has been found that the use of clay mineral functionalized by hydrocarbon-substituted nitrogen compounds allows co-encapsulation of several types of biocidally active ingredients which otherwise can not be inserted into the interlayer of the clay mineral without the presence of the hydrocarbon-substituted nitrogen compounds.